1. Field of the Invention
The present invention relates to recreational vehicles and, in particular, relates to a lifting and lowering system for slide-out assemblies in recreational vehicle housings.
2. Description of the Related Art
Recreational vehicles are becoming increasingly popular with people who wish to retain the comforts and conveniences of home while spending extended periods of time away from home at remote locations. In more elaborate configurations, the recreational vehicle typically includes amenities such as a bedroom, a bathroom with a sink and a flushing toilet, a kitchen with a refrigerator, stove, and sink, and a generously sized living area with reclining chairs and an entertainment center. Furthermore, a recreational vehicle may be easily parked at a wide variety of locations so that users may enjoy the amenities of the vehicle at their favorite destination. Consequently, people who use recreational vehicles may usually be assured of a comfortable living environment at their preferred remote destination without having to rely on the availability of suitable hotels.
In response to consumer demand, manufacturers have developed increasingly larger recreational vehicles. In particular, manufacturers have developed recreational vehicles with one or more extendable structures, commonly referred to as slide-outs, that provide the user with a supplemental living space when the vehicle is parked in a suitable location. The extendable structure is adapted to extend into a deployed configuration during the time that the vehicle is parked so that the interior living space within the recreational vehicle is increased by an amount which is, substantially equal to the supplemental living space of the extendable structure. The extendable structure is also adapted to retract into a retracted configuration during the time that the vehicle is in motion or towed so that the traveling dimensions of the recreational vehicle are within the maximum allowed length and width.
The typical extendable structure or slide-out is positioned within an opening of the housing of the recreational vehicle and is comprised of a plurality of walls that form the supplemental living space therein and an opening that provides access to the supplemental living space. In particular, the walls of the slide-out may comprise an upper horizontal wall that forms either a single level planar ceiling, which may substantially align with an adjacent ceiling of the vehicle, or a step configuration, wherein the ceiling of the slide-out is dimensionally lower than the ceiling of the adjacent ceiling of the vehicle. In addition, the extendable structure or slide-out may also comprise an outer vertical wall that is adapted to align with an outer wall of the motorhome or travel trailer, when the slide-out is placed in the retracted configuration. In addition, a pair of horizontal sidewalls may be utilized to join the upper and lower horizontal walls and the outer vertical wall together.
Moreover, the walls of the typical slide-out are comprised of a lower horizontal wall that forms a single level planar floor, which substantially aligns with an adjacent floor of the vehicle housing. Typically, the slide-out is typically lowered after deployment of the slide-out from the vehicle housing so that the lower horizontal floor forms a single level planar floor with the vehicle housing floor. Also, the slide-out typically lifted prior to retraction of the slide-out within the vehicle housing.
Conventional lifting and lowering systems for slide-outs use an inclined surface at the lower edge of the opening in the vehicle housing and wheel, roller, or friction pads fixed to the inclined surface mounted to the lower inside edge of the slide-out. During retraction, the wheel rolls up the incline prior to retraction of the slide-out into the vehicle housing or the floor of the room slides over the fixed fraction pads in an inward manner. During deployment, the slide-out is extended out of the vehicle housing and then the wheel engages the inclined surface to lower the slide-out into position or the floor of the room slides over the fixed fraction pads in an outward manner.
Unfortunately, the inclined lower edge of these sidewall openings can be difficult to manufacture due to the structural bends that need to be formed so as to accommodate the sloped surface. Also, the structural integrity of the incline lower edge is compromised by welded components that are inadequately supported and structurally unsound. As a result, due to deployment/retraction stresses on these deficient structures, the inclined lower edge of the sidewall openings can weaken over time. From the foregoing, there currently exists a need to improve the manner in which the slide-out is lifted and lowered during retraction and deployment.